This project will develop new methods for measuring the quality of care for a vulnerable population: very low birth weight infants, defined as those infants who weigh 1500 grams or less at birth. These infants are vulnerable in many ways. First, one in four infants born with a birth weight of 1500 grams or less will not survive to the end of the first year of life. While they account for only 1 percent of births, very low birth weight infants account for 46 percent of infant deaths. Second, infants with birth weights 1500 grams or less have high rates of disability. In fact, birth weight under 1200 grams is a qualifying condition for the Supplemental Security Income (SSI) Program, which provides income support and health insurance coverage for disabled children. Third, very low birth weight infants are disproportionately born in black, low-income families, with Medicaid being the largest single payer for their medical care. Little is known about the quality of care for this patient population because of methodological challenges and the lack of available data. In this project we will: Develop methods to measure the quality of care for high-risk infants that overcome the problems of small sample sizes, bias from patient mix, and the multidimensionality of quality. Use these methods to create "filtered" estimates of the quality of care which extract the quality "signal" from the noise observed in the data. Apply similar methods to measuring economic performance and to quantify the relation between hospital characteristics, such as volume and NICU level, on the quality of care provided to very low birth weight infants. To overcome the data problems, we will use a unique source of data, the Vermont Oxford Network (VON) database, which contains 40 percent of NICUs in the United States and includes half of all very low birthweight births in the county each year. The quality measures developed will be implemented by the Network within two years of the initiation of this project, thus having the potential to rapidly influence the care received by a large number of these fragile infants.